Today, the police of England and Wales have wider sampling powers than the police force of any other country, and the UK has (proportionally, per head of population) the largest forensic database in the world.

When the police first began using DNA, consent was required before samples could be taken. A succession of Acts of Parliament and legislative amendments has increased police powers of sampling; the police can now take DNA samples from all persons arrested, without their consent, for recordable offences (an "arbitrary" classification), and retain the samples indefinitely regardless of whether the person arrested is subsequently convicted or even charged.

In response to comments from the Home Office that retaining the DNA of people who were innocent at the time of arrest had helped to solve crimes they committed years later, the Nuffield Council stuck to its guns. "There has to be a limit to police powers," said Dr Carole McCartney, one of the report's authors. "DNA shouldn't be retained simply on the basis that it might turn out to be useful."

She added that many of the statistics from the Home Office were "inconsistent, incomplete and confusing" and that much of its evidence consisted of anecdotal accounts of "horrible men caught with DNA".

The council recommended that the police should put more resources into the collection of DNA from crime scenes, noting that less than 20 per cent of crime scenes are forensically examined, but urged caution with regard to their analysis.

Professor Read outlined some of the information that could be mined from a data rich bio-sample found at the scene of a crime. Conceding that recent advances permitted forensic scientists to have a "pretty good stab at the eye colour", and quickly identify redheads, ethnic profiles generated by DNA analysis were still limited to providing a "very iffy statistical prediction" and there was a danger that such predictions encouraged the police to narrow the focus of their inquiries prematurely.

The council rejected calls for a population-wide database, which would "make all citizens suspects", on account of the lack of empirical evidence that this would substantially improve crime detection rates. It dismissed the "nothing to hide, nothing to fear" argument as "fallacious".

The finding of a match between a person and a crime scene does not indicate that the person was at the crime scene or that they committed the crime in question, but it might lead to them being subjected to a police investigation.

The report points out that "simply being the subject of a criminal investigation by the police can cause harm, distress, and stigma", and Sir Bob Hepple QC, chairman of the Nuffield Council on Bioethics, cited a newspaper comment on the McCann case that the couple would find it "difficult to prove their innocence" as a result of widely reported forensic links.

Concern was also expressed about new uses to which the database is now being put and the acute lack of ethical oversight. The original aim of the DNA database was to match crime scene samples to suspect samples. It is now being used for "increasingly speculative searches", including "ethnic inferences" and "genetic predisposition to crime".

Council members have been unable to discover the nature of all the research projects permitted by the DNA Database Custodian, and criticise the lack of transparency over the granting of third party requests for access to the database.

In light of the shifting applications of genetic information, the council recommends those who voluntarily provide the police with their DNA, including victims and witnesses, should be able to have it removed from the National DNA Database at any time without having to give a reason.

Currently, a volunteer's decision to consent at the time of sampling to their profiles being permanently loaded onto the database is irrevocable. This is in direct contrast to standard practice in medical research.

There is no framework in place for regulating international exchange of data between law enforcement agencies, compounding the council's concerns about potential misuses of the database.

The council recommends that the Government, as a matter of urgency, examine the implications of sharing the DNA material of UK citizens with foreign law enforcement agencies and private forensic science companies. Analysis and storage of biological samples is currently performed by three companies, and this number is set to rise.

GeneWatch alerted the public to the insecurity of the DNA database in 2006 when it obtained disclosure of confidential emails revealing that LGC, a company used by the police to analyse DNA samples, had been secretly keeping the genetic samples and personal details of hundreds of thousands of people.

The Nuffield Council recommends that the organisations and companies with custody of biological samples complete a standard Material Transfer Agreement, subject to ethical review, that establishes the terms and conditions under which samples may be accessed.

During the public consultation exercise, a number of people expressed grave concern about health-related information that might be obtained from the bio-samples. Unfortunately, the report fails to address this concern in any detail, and Professor Read said he found it "difficult to imagine what possible use the police could make of such information".

The report refers to the potential use of genetic material to satisfy the search for specificity by "less than lethal" weapon enthusiasts, and cites a paper by two Chinese authors in the 2005 Military Review in which they state: "If we acquire a target's genome and proteome information, including those of ethnic groups or individuals, we could design a vulnerating agent that attacks only key enemies without doing any harm to ordinary people". ®

Amber Marks is a lawyer, currently undertaking research into surveillance. Her book Headspace: On the Trail of Sniffer Dogs, Wasp Wardens, and Other Dumb Friends in the Surveillance Industry is due to be published by Virgin Books in March 2008.